Field of the Invention
The present invention relates to a pneumatic tire.
Description of the Related Art
As a pneumatic tire, a tire having a tread pattern including a plurality of main grooves extending in a tire circumferential direction on a tread portion, and a plurality of land portions partitioned by the main grooves and provided with lateral grooves and sipes is known. A tire having such a tread pattern is generally subjected to deterioration of road-hugging property or generation of uneven wear due to non-uniform ground contact pressures of the plurality of land portions because the lateral grooves and the sipes are not provided evenly on the plurality of land portions.
JP-A-2005-263180 discloses a configuration in which ground contact areas of ribs formed between main grooves are protruded radially outward of a tire with respect to an outer contour line passing through the ground contact areas of shoulder ribs, and protruded apexes of the respective ribs are shifted inward with respect to center lines of the respective ribs in a state of being mounted on a vehicle in order to improve driving stability at the time of cornering by improving a ground-contact shape.
JP-A-2013-189121 discloses a configuration in which the ground contact areas of a center land portion and intermediate land portions are protruded by a predetermined amount radially outward of the tire with respect to a reference contour line of a tread portion and an amount of protrusion of the center land portion is formed to be larger than that of intermediate land portions in order to improve the road-hugging property entirely in a tire width direction of the tread portion and improve driving stability.
In this manner, JP-A-2005-263180 discloses a configuration in which the ground contact areas of the plurality of land portions are protruded and the protruded apexes are set to positions shifted from widthwise centers of the land portions, and JP-A-2013-189121 discloses a configuration in which the ground contact areas of the plurality of land portions provided on the tread portion are protruded by different amounts of protrusion. However, in these documents, non-uniformity of the ground contact pressure caused by the lateral grooves and the sipes provided on the land portions when protruding the ground contact areas of a block is not considered, so that deterioration of the road-hugging property and generation of uneven wear may not be restricted.